In a touch sensing system, a proximity image may be obtained from a touch sensing surface, and the image may be segmented into a plurality of patches, each corresponding to a contact on or near the touch sensing surface. An ellipse may be fit to each of the plurality of patches. The parameters of the ellipse may be used to identify the contact patches and generate input. However, when a contact patch is on the edge of a proximity image, a fitted ellipse may not accurately represent the sensed touch object, some of which may be past the edge of the touch sensing surface.